Structural Adhesive Films

AF 6 • AF 10 • AF 13

Cure Cycle

3M™ Scotch-Weld™ Structural Adhesive Films AF 6, AF 10 and AF 13

General Cure Requirements: Time, temperature and pressure determine final bond

properties. These properties may also be effected by the type of curing equipment

used for each specific application. In general, cure properties are as follows:

Tack, Flow and Cure Initiation Temperatures

Tack, flow and cure initiation temperatures are a time temperature relationship which

depend upon the rate of heat input. Normally the properties are as follows:

Tack Temperature:

160°F-180°F (71°C-82°C)

Flow Temperature:

180°F-220°F (82°C-104°C)

Cure Initiation Temperature:

220°F-270°F (104°C-132°C)

Cure Pressure: Pressure is required during cure to form the part being bonded and to

contain any volatiles given off by the adhesive. Cure pressure may be applied in any

manner which will ensure uniform constant pressure throughout the bond area.

Pressure must be uniformly applied before the curing reaction begins and maintained

until a complete set has been effected. The pressure required to contain volatiles is

dependent on the rate at which bond line temperature is brought to the cure

temperature. The bond line temperature rise rate can be varied from 1°F to

300°F/minute (0.6°C to 167°C/minute). Rise rate (and cure pressure required) will

depend on specific application, cure temperature, bonding equipment, method of heat

application, production limitations and bond properties required.

Cure Temperature: Cure temperature may be varied from 275°F to 400°F (135°C to

204°C), depending upon the materials being bonded, equipment available and bond

properties desired. The desired pressure must be applied before the glue line reaches

160°F (71°C). Film will soften as temperature is increased to 180°F-220°F (82°C-

104°C) and will wet the surface to which it has been applied. A chemical cure will be

initiated between 220°F and 270°F (104°C and 132°C) and a low strength gel

formed. Continued heating chemically, converts the adhesive into a high-strength,

solvent-resistant bond.

Cure Time: Cure time depends on the cure temperature used, methods of heat

application, production limitations and bond properties required. Since no two

bonding operations are exactly alike, it is suggested that a few simple experiments be

conducted, varying both temperature and cure time to determine optimum conditions

for the particular application.

Suggested Cure Cycle: The following press cure cycle is suggested to obtain dense

glue lines and was used to obtain the strengths reported in the test results section.

1. Place bonds in press and apply 150 psi (1.03 MPa) of pressure.

2. Temperature rise rate 10°F/minute from ambient to 350°F (6°C/minute from

ambient to 177°C).

3. Cure for 60 minutes at 350°F (177°C).

4. Bonds can be removed from the press at 350°F (177°C).

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